Classifications

• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/74—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing arsenic, antimony or bismuth
  • C09K11/7407—Chalcogenides
  • C09K11/7414—Chalcogenides with zinc or cadmium
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/30—Identification or security features, e.g. for preventing forgery
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/30—Identification or security features, e.g. for preventing forgery
  • B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B42—BOOKBINDING; ALBUMS; FILES; SPECIAL PRINTED MATTER
  • B42D—BOOKS; BOOK COVERS; LOOSE LEAVES; PRINTED MATTER CHARACTERISED BY IDENTIFICATION OR SECURITY FEATURES; PRINTED MATTER OF SPECIAL FORMAT OR STYLE NOT OTHERWISE PROVIDED FOR; DEVICES FOR USE THEREWITH AND NOT OTHERWISE PROVIDED FOR; MOVABLE-STRIP WRITING OR READING APPARATUS
  • B42D25/00—Information-bearing cards or sheet-like structures characterised by identification or security features; Manufacture thereof
  • B42D25/30—Identification or security features, e.g. for preventing forgery
  • B42D25/36—Identification or security features, e.g. for preventing forgery comprising special materials
  • B42D25/378—Special inks
  • B42D25/387—Special inks absorbing or reflecting ultraviolet light
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/56—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing sulfur
  • C09K11/562—Chalcogenides
  • C09K11/565—Chalcogenides with zinc cadmium
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/58—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing copper, silver or gold
  • C09K11/582—Chalcogenides
  • C09K11/584—Chalcogenides with zinc or cadmium
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/61—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing fluorine, chlorine, bromine, iodine or unspecified halogen elements
  • C09K11/611—Chalcogenides
  • C09K11/612—Chalcogenides with zinc or cadmium
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/62—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing gallium, indium or thallium
  • C09K11/621—Chalcogenides
  • C09K11/623—Chalcogenides with zinc or cadmium
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/64—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing aluminium
  • C09K11/641—Chalcogenides
  • C09K11/642—Chalcogenides with zinc or cadmium
• • C—CHEMISTRY; METALLURGY
  • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
  • C09K—MATERIALS FOR MISCELLANEOUS APPLICATIONS, NOT PROVIDED FOR ELSEWHERE
  • C09K11/00—Luminescent, e.g. electroluminescent, chemiluminescent materials
  • C09K11/08—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials
  • C09K11/64—Luminescent, e.g. electroluminescent, chemiluminescent materials containing inorganic luminescent materials containing aluminium
  • C09K11/644—Halogenides
• • D—TEXTILES; PAPER
  • D21—PAPER-MAKING; PRODUCTION OF CELLULOSE
  • D21H—PULP COMPOSITIONS; PREPARATION THEREOF NOT COVERED BY SUBCLASSES D21C OR D21D; IMPREGNATING OR COATING OF PAPER; TREATMENT OF FINISHED PAPER NOT COVERED BY CLASS B31 OR SUBCLASS D21G; PAPER NOT OTHERWISE PROVIDED FOR
  • D21H21/00—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties
  • D21H21/14—Non-fibrous material added to the pulp, characterised by its function, form or properties; Paper-impregnating or coating material, characterised by its function, form or properties characterised by function or properties in or on the paper
  • D21H21/40—Agents facilitating proof of genuineness or preventing fraudulent alteration, e.g. for security paper
  • D21H21/44—Latent security elements, i.e. detectable or becoming apparent only by use of special verification or tampering devices or methods
  • D21H21/48—Elements suited for physical verification, e.g. by irradiation
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/005—Testing security markings invisible to the naked eye, e.g. verifying thickened lines or unobtrusive markings or alterations
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
  • G07D7/12—Visible light, infrared or ultraviolet radiation
• • G—PHYSICS
  • G07—CHECKING-DEVICES
  • G07D—HANDLING OF COINS OR VALUABLE PAPERS, e.g. TESTING, SORTING BY DENOMINATIONS, COUNTING, DISPENSING, CHANGING OR DEPOSITING
  • G07D7/00—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency
  • G07D7/06—Testing specially adapted to determine the identity or genuineness of valuable papers or for segregating those which are unacceptable, e.g. banknotes that are alien to a currency using wave or particle radiation
  • G07D7/12—Visible light, infrared or ultraviolet radiation
  • G07D7/1205—Testing spectral properties

Definitions

• the invention relates to a powdery zinc sulfide phosphor which is excited by an electric field as electroluminophor and beyond specific Lumineszenzei ⁇ properties has. More particularly, the invention relates to a zinc sulfide electroluminescent pigment which characteristically differs from the electroluminophores used in conventional thick film electroluminescence (ACPEL) applications and which, for this reason, is advantageously used as a security feature in security documents can. In addition, the invention relates to a method for producing a zinc sulfide phosphor and a security feature, a security document and a
• Powdered zinc sulfide electroluminophores and entspre ⁇ -reaching ACPEL applications have long been known.
• the electroluminescent ZnS phosphors are mostly copper
• the grain size of the synthesized materials is generally in ym
• the application is usually in the form of so-called electroluminescent, in which the phosphor particles are arranged in the sense of a capacitor arrangement between two electrodes and insulating layers and when creating a emit light of usually 110 V and 400 Hz light in the blue, green or orange range of the visible spectrum.
• Rolumineszenzfolien Examples of such elec- or lamps are display, illuminations background reports, lighting and marking items as they testify Flight ⁇ and motor vehicles, are used in buildings or for the production of advertising installations.
• the zinc sulfide phosphor particles used for the production of known electroluminescent films are used for
• This coating which is also referred to as microencapsulation, can be carried out, for example, with the aid of processes such as chemical vapor deposition.
• the individual phosphor particles completely enveloping layers may, for example, of SiC> 2, Ti0 2, A1 2 0 3 (see. US 5,156,885 A, US 5,220,243 A), from the Oxynitri- which the elements Al, B, Si, Ti (see WO 00/022064 A1) or A1N (cf., EP 0 938 826 Bl).
• Security documents and value printing such as in banknotes, passports, identity cards, driving licenses, etc. to use (see EP 0 964 791 Bl).
• the zinc-sulfidic electroluminophores used in these cases are usually applied on the basis of conventional printing technologies (for example gravure printing, offset printing or screen printing methods) in or on the matrix of the respective security documents
• Paper, plastics, laminated plastics or else can be made of other suitable materials, arranged, without thereby ⁇ a classic capacitor structure aspires ⁇ or is realized.
• the thus applied electroluminophores preferably contactless excited by electric fields, because of the specific and unconventional arrangement of the electroluminescence neszenzpigmente in the matrix of the security document in general, relatively high-frequency high voltage fields necessary to secure stationary and vorteilhaf ⁇ ingly also a high-speed detection of the resulting luminescence to (see EP 1 059 619 B1, EP 1 149 364 Bl and DE 10 2008 047 636 AI).
• An increase in the effective at the electroluminescent local field strength of the impressed electroluminescence electric alternating fields can also be achieved that in addition to the EL pigments and in close proximity to them so-called field displacement elements in the corresponding security markings of security and / or value documents are arranged ( see EP 1 631 461 B1, EP 1 748 903 B1).
• the field displacement elements are isolated, electrically conductive pigments with high dielectric constants, either metallic particles consisting of iron (Fe), copper (Cu), aluminum (AI) and / or silver (Ag), or certain transparent, optically variable multilayer effect pigments are used.
• the feature can not only the level-3 characteristic and a corresponding level-l characteristic exhibit.
• the visual effect of these pigments which, in a color change perceptible to the observer, differs under different lighting conditions
• Viewing angles can be used as an additional feature in the authenticity verification.
• ZnS phosphors doped with different activator ions can also be excited to luminescence with electromagnetic radiation (for example with UV or X-rays) or else with the aid of electron beams.
• electromagnetic radiation for example with UV or X-rays
• phosphors for classical Color tubes corresponding applications ⁇ or as afterglow have a long tradition.
• carthodolumines- zinc sulfide phosphors usually show no or at least no verwert ⁇ bare electroluminescence. The same is true in the opposite sense: both the EL and EL applied in conventional technical applications as well as in security and value documents.
• Pigments are generally not or only extremely weakly excitable by luminescence due to electromagnetic radiation and electron beams, which is due to the fundamentally different luminescence mechanisms of the different types of luminescence and to the compositions of the EL pigments specially selected for achieving high elec- troluminescence yields and to the specific production techniques due ⁇ gies (cf. Shionoya, S; yen, WM.. "phosphor Handbook", CRC Press, 1999, pages 581-621).
• the production takes place according Zinc sulphide electroluminophores based on a solid-state chemical More ⁇ gradual process. From the prior art, inter alia from EP 1 151 057 Bl, the following steps to be carried out successively are known:
• Security features apply. Further obstacles to the use of such security features may include, for example, that environmental regulations or safety regulations do not allow to realize the required for the authenticity verification excitation of the EL pigments with divefre ⁇ quent electrical high voltage alternating fields. Restrictions of the type described can, for example, apply to the verification of electroluminescent features in banknotes if the authenticity check is to be carried out in decentralized sorting systems or else in cash machines for individual cash withdrawal or cash deposit. In such cases, it would be of great benefit if the electroluminescent feature had further properties independent of its level-3 characteristic, which could also be used for authenticity verification, without revealing the operating principle of the level-3 safety feature.
• the real ⁇ comprehensive detection of the feature should in this alternative method (Level 2 status) using comparatively easy to handle detection means may be possible.
• the object of the invention is to provide an altered zinc sulfidic electroluminescent which furthermore has its electroluminescent property but moreover has at least one further property that can be evaluated as a security feature.
• the invention is intended to provide a corresponding production method and a method based on this phosphor. security feature, a security document with such a security feature, and a method for detecting the additional exclusive features of the security feature in corresponding security documents.
• the object is achieved by a zinc sulfide phosphor according to the appended claim 1.
• the object is further achieved by a method for producing a zinc sulfide phosphor according to the appended subordinate claim 4 and by a producible by this method phosphor according to the attached independent claim.
• 9 the object is achieved by a security feature according to the attached independent claim 10, by a security or value document according to the attached independent claim 11 and by a
• the inventive, preferably powdered, zinc sulfide ⁇ luminescent phosphor shows in addition to its specific
• Electroluminescence an intense and thus detectable by conventional sensors photoluminescence, which is also characterized by a characteristic color change with variation of the UV excitation conditions.
• Fluorescent a characteristic blue and / or green Elek ⁇ rolumineszenz and also blue emission on excitation in the wavelength range between 345 nm and 370 nm, while in contrast to the excitation with a shorter wavelength UV radiation in the wavelength range between 310 nm and 335 nm green light emits.
• the phosphor thus emits either blue or green photoluminescence. This one from the electric Luminescence independent color change of the UV-stimulable Photolu ⁇ mineszenz can be exploited as an additional authenticity criterion in the application of the phosphor according to the invention in security ⁇ features.
• the described exclusivity and complexity of the luminescence behavior is linked to a specific phosphor composition which is given below.
• the zinc sulfide phosphor of the present invention has the following general chemical formula:
• ZnS A a , M b , X c with 0 ⁇ (a + b + c) ⁇ 0, 12;
• A is Cu, which may be proportionally replaced by Ag and / or Au.
• the phosphor basically comprises Cu as an activator.
• A is exclusively Cu.
• M stands for AI, which is proportional to one or more
• Metals can be replaced, which are selected from the elements comprising Bi, Ga and In comprehensive group.
• the phosphor basically includes Al.
• M stands exclusively for Al.
• X represents one or more halides which occur as monovalent anions X.sup. + And are selected from the group comprising elements F, Cl, Br and I.
• the ions M and X act as coactivators.
• the exact lattice positions on which the ions of A, M and X are built in can not be determined. Also in the scientific literature exists with comparable
• the phosphor of the invention may include minor amounts of other elements, provided these do not affect his og charac ⁇ ristic properties and do not delete the emission intensities an unacceptable degree.
• alkali or alkaline earth ⁇ elements are analytically detectable, if they had been added in the form of their halides the batch mixture. So far, it is not clear whether these elements fit into the
• Base grids are installed or if they are present as non-washable inclusions in the phosphor. Their presence does not lead to a change in the properties of the inventive phosphor. Thus, the presence or absence of alkali or alkaline earth ions is not a feature that goes beyond the present invention.
• the phosphor according to the invention has the following composition:
• the phosphor according to the invention is preferably in the form of a powder, the average particle size preferably being between 2 ⁇ m and 50 ⁇ m; more preferably between 2 ym and 20 ym.
• Another object of the invention is a method for producing a zinc sulfide phosphor, in particular the zinc sulfide phosphor according to the invention.
• Matrix is influenced not only by the specific phosphor composition according to the invention but also to a great extent by preparative factors.
• the method first comprises a step of providing Stel ⁇ development of the starting compounds.
• the main constituent of the reaction mixture is the zinc sulfide (ZnS), it being possible where appropriate to additionally add certain amounts of sulfur (S) to this base substance.
• S sulfur
• elemental sulfur is used as a further starting material and with the optionally
• a copper (Cu) -containing chemical compound is provided as a raw material.
• the copper (Cu) required as activator for the synthesis according to the invention of the zinc sulfide electroluminophore is generally introduced into the mixture of the starting materials as copper sulfate (CUSO 4 ).
• the chemical compound comprising the copper is preferably copper sulfate.
• an Ag-containing chemical compound and / or Au contained ⁇ tends chemical compound can be used.
• the Ag-containing compound is preferably AgNC> 3 .
• the compound containing the Au is preferably a 3 [AUCI 4 ].
• an Al-containing chemical compound is provided.
• a Bi-containing chemical compound, a Ga-containing chemical compound and / or a chemical compound containing In may also be added Be provided starting material.
• the chemical compound containing the aluminum (AI) may be
• Al 2 O 3 alumina
• Al (OH) 3 aluminum hydroxide
• Al (OH) 3 aluminum sulfate
• Al nitrate A1 (03)
• Al sulfide Al 2 S3
• AIX 3 with X F, Cl, Br, I
• Al nitride Al nitride
• halide X-containing chemical compound is provided.
• the formula symbol X stands for one or more elements selected from the elements F, Cl,
• the formula Symbol X is in ⁇ Trains t for I.
• the iodine (I) passes, as well as the other halides described in the general formula, usually (in the form of the corresponding alkali metal (such as Lil, Nal, KI), alkaline earth metal, for example, Mgl 2 , Cal 2 , Bal 2 ) or Ammoniumver ⁇ bond (NH 4 I) or as bismuth iodide (B1I 3 ) to
• the compound containing Al, Bi, Ga or In and the compound containing the halide X may be identical, e.g. As aluminum halide (AIX3) or as bismuth halide (BiX 3 ).
• Some of the chemical compounds provided as starting materials for carrying out the process may be used in following thermal treatment also act as a flux.
• the chemical compounds provided may need to be ground.
• the present in powder form chemical compounds are first mixed together to form a mixture.
• the mixture is then calcined at temperatures between 800 ° C and 1200 ° C, possibly also up to 1300 ° C, whereby the in the
• the mixture is annealed in the presence of activated carbon, the presence of which plays an important role in the adjustment of the local annealing atmosphere necessary for the preparation of the inventive phosphor.
• the high-temperature annealing process takes place
• the annealing of the mixture is preferably carried out in a weakly reducing atmosphere of nitrogen 2 and hydrogen H 2 , with 1% to 6% hydrogen.
• the weak reducing atmo sphere ⁇ is particularly preferred CLU S 5% hydrogen and 95% nitrogen; alternatively preferably from 1.5% hydrogen and 98.5% nitrogen.
• the annealing takes place under stagnant air.
• the mixture is preferably in a glowing crucible during the annealing process, for example in a fused silica shell or in an aluminum oxide boat.
• a fine adjustment of the local annealing atmosphere in the individual annealing crucible is made such that within the covered annealing crucible and above the compressed mixture activated carbon is positioned, for example, by a smaller filled with activated carbon graphite crucible.
• the presence of the activated carbon is realized, thereby making it possible to control the annealing atmosphere and prevent the early subli ⁇ mation of Schmelzsch- and / or Koentatorzu algorithmsn.
• the mass of the activated carbon present is preferably between 0.0001 and 0.1 of the mass of the zinc sulfide, more preferably between 0.0005 and 0.05 of the mass of the zinc sulfide.
• the activated charcoal ⁇ is preferably disposed in a graphite shell, which is arranged above the compressed mixture.
• the annealing of the mixture preferably takes at least two stun ⁇ . It is preferably carried out at temperatures between 850 ° C and 1200 ° C.
• the formed phosphor is then allowed to cool. Then, according to one embodiment, it is ground, washed, dried and sieved. In this simple case, the phosphor is then available without further required process steps. It has surprisingly shown that it can be for the off ⁇ formation of the special properties of the zinc sulfide phosphor advantageous according to the invention to dispense with a Nachdotieren the present after the high temperature annealing annealing charge with additional copper.
• the desired luminescence properties of the phosphor according to the invention can thus be achieved with a drastically reduced process outlay, namely without the step of postdoping in the case of zinc sulfide phosphors, which have exclusively or mainly electroluminescent properties.
• the workup of the annealing can then be done simply by gentle, deagglomerating wet grinding and performing several washing processes. Consequently, in these embodiments, no treatment with a dilute mineral acid, no post-doping of the intermediate with Cu and no renewed
• the phosphor obtained after the high-temperature annealing process is initially an intermediate product.
• This intermediate is cooled Help ⁇ before the further steps and washed with H 2 O. Furthermore, a deagglomeration of the intermediate product is carried out using ceramic balls and with the addition of a grinding aid, such as choline base, pyrophosphate solution or potash waterglass solution. Finally, a treatment with dilute mineral acid, whereby in particular the surfaces of the powder grains of the intermediate product are modified.
• the mineral acid is preferably formed by hydrochloric acid.
• a post-doping of the intermediate product with Cu whereby the herzustel ⁇ luminescent phosphor is formed. The post-doping takes place in that Cu is in the form of a Cu-containing chemical
• the post-doped phosphor is preferably tempered, at a temperature between 200 ° C and 600 ° C, more preferably between 300 ° C and 500 ° C. Annealing preferably takes Minim ⁇ least one hour.
• the post-doped phosphor may be considered again as an intermediate of another modified embodiment, and in this case is treated with a dilute mineral acid after it has been tempered.
• the dilute acid is preferably formed by dilute nitric acid. After treating with the dilute acid, this intermediate is washed again, dried and tempered. The renewed
• Annealing is preferably carried out at a temperature between 200 ° C and 500 ° C and leads after cooling to the modified zinc sulfide phosphor.
• the setting of the preparative conditions is important for the inventive preparation of the zinc sulfide phosphor. Starting from the preparation disclosed herein steps optimized synthesis conditions can be experimentally easily be found if necessary ⁇ despite the complexity of the characteristic fluorescent properties of Elektroluminophors and despite the different A ⁇ flow preparative factors. If necessary, only a few experiments to be carried out under laboratory conditions are required. On the other hand, it should be expressly stated in this context that the synthesis of the phosphor according to the invention can be supplemented by further process steps known per se.
• the phosphor prepared in the manner described generally has well deagglomerated particles with average grain sizes between about 2 ym and about 20 ym.
• the Korngrö ⁇ size distributions can be controlled by the preparation conditions and set.
• the mean grain sizes of the electroluminophore according to the invention are not limited to the range exemplified.
• the phosphor according to the invention is preferably characterized by the process according to the invention for its preparation and by the specific phosphor composition described.
• Another object of the invention is formed by a zinc sulfide phosphor which can be produced by the process according to the invention.
• Phosphor is preferably produced by preferred embodiments of the method according to the invention.
• This zinc sulphide phosphor has in particular the above
• this zinc sulfide phosphor has the above-described feature that Cu forms an activator and that M and X form coactivators, whereby two different activatable radiation centers in the zinc sulfide phosphor are caused by Cu and by M and X.
• the security feature according to the invention comprises one or more embodiments of the zinc sulfide phosphor according to the invention.
• the security and / or value document according to the invention may be, for example, a banknote or a passport, an identity card, a driver's license or a stamp. It includes a security feature, comprising one or more embodiments of the erfindungsge ⁇ MAESSEN zinc sulfide phosphor.
• the security feature can ⁇ in different ways or in the
• the security feature using suitable printing technologies, such as with a gravure, offset printing or
• the field displacement elements are electrically conductive ⁇ and electrically isolated within the security document. They have a high dielectric constant. They are preferably arranged in close proximity to the zinksulfidi ⁇ rule phosphor.
• the FeldverdrDeutschungsele ⁇ elements preferably consist of metallic particles such as iron (Fe), copper (Cu), aluminum (AI) and / or silver (Ag) or even transparent, optically variable multi-layer effect pigments.
• the field displacement elements serve to increase the effective at the zinc sulfide phosphor local field strength of the electric field.
• a further subject of the invention is a method for detecting and / or verifying a security feature comprising a phosphor in a security or value document. The method preferably serves for the detection and / or verification of the phosphor according to the invention or of a security feature formed therewith in the respective one
• the phosphor is excited by an electric field.
• the phosphor is thus excited as an electroluminophore. Accordingly, it is checked whether an electroluminescence in the blue and / or green region of the light spectrum can be received, which is emitted by the phosphor due to the excitation by the electric ⁇ cal field.
• the excitation is preferably carried out by a high-frequency high-voltage field, which is aligned to the luminescent ⁇ material to allow a safe stationary and vor ⁇ geous way, a high-speed detection of the receivable luminescence signals.
• the phosphor is excited by irradiating the phosphor with UV radiation in the wavelength range between 345 nm and 370 nm. Accordingly, it is checked whether a photoluminescence in the blue region of the light spectrum can be received, which is from the Phosphor is emitted as a result of the excitation by the UV radiation in the wavelength range between 345 nm and 370 nm.
• the phosphor is excited by irradiating the phosphor with UV radiation in the wavelength range between 310 nm and
• UV radiation is emitted in the wavelength range between 310 nm and 335 nm. If by the method according to the invention, a phosphor or a corresponding security feature with high reliability sketchsi ⁇ (improved as a Level-3) to be tested, all three emission occurring are checked and verified.
• the phosphor according to the invention is examined in addition to the electroluminescent whether a more independent of the Elect ⁇ rolumineszenz color change of the excited with shorter- or longer-wave UV radiation photoluminescence can be detek- advantage.
• the illustrated excitations and detections can occur simultaneously, consecutively or alternatively to one another.
• the excitation of the level 3 feature electroluminescence is dispensed with and only the based on the color shift of the resulting at varying UV excitation wavelengths photoluminescence emissions level
• the excitation and detection can be separated in time and space or at the same time in a compact apparatus.
• the security document is preferably detected and / or verified if the electroluminescence in the blue and / or green region of the light spectrum, the photoluminescence in the blue region of the light spectrum and the photoluminescence in the green region of the light spectrum were received. This sets furthermore, that the photoluminescence in the blue region of the light spectrum was received exclusively during the excitation of the phosphor by the UV radiation in the wavelength range between 345 nm and 370 nm, and that the
• FIG. 1 shows emission spectra of a first general embodiment of the phosphor according to the invention
• FIG. 2 shows emission spectra of a second general embodiment of the phosphor according to the invention
• FIG. 3 shows emission spectra of a first preferred embodiment of the phosphor according to the invention
• Fig. 5 emission spectra of a third preferred embodiment of the phosphor according to the invention.
• the phosphor emits broadband in the blue spectral range with a maximum wavelength X max of about 450 nm both in the case of EL and UV-A excitation.
• X max maximum wavelength
• the photoluminescence 02, 03 thus has a considerable color shift, which is about 70 nm on the basis of the distance of the maximum wavelengths.
• Fig. 2 corresponding emission spectra 11, 12, 13 are shown for a further exemplary general embodiment of the inventive phosphor. In this case as well, there is a marked color shift between UV-A excited photoluminescence 12 and UV-B excited photoluminescence
• the zinc sulfide electroluminophor invention can, as known from the prior art electroluminescence mine ornamental EL pigments and advantageously in place of those times for the purpose of protection against forgery as security features in security and valuable documents such as banknotes, travel ⁇ passports, identity cards, driving licenses, Identity cards, access cards, health insurance cards, postage stamps, bank cards, credit cards, smart cards, tickets or
• the phosphor is made using standard printing technologies such as flexo,
• the EL phosphor according to the invention can also be mixed with the described field displacement elements.
• the selection of the printing method to be used is then dependent inter alia on the set grain size distribution of the inventive electroluminophore and on the added field displacement elements.
• the identification of the level-3 characteristic of the security feature based on the phosphor according to the invention is achieved by the excitation of the phosphor particles with high-frequency high-voltage alternating fields.
• the crucial advantage of the erfindungsge ⁇ MAESSEN phosphor and its subsequent invention shown SEN security feature is that they have at least one further exclu- sive fluorescent property with Level 2 status in addition to the special Elektrolumineszenz characterizing, the corresponding additionally or alternatively to Elektrolumineszenzpphrasenomen for authenticity verification Security or value documents can be used. This concerns the
• So-called field displacement elements used in the form of electrically conductive, optically variable effect pigments so the feature in addition to the level 3 and the level 2 - status also have a corresponding level 1 character integrating.
• the optical effect of these pigments which consists in a perceptible color change to the viewer at different illumination and viewing angles, can be used as an additional feature in the Echtheitsverifika ⁇ tion.
• the described features of the phosphor according to the invention thus make it possible to generate luminescent security features which have all classified authenticity characteristics to be assigned to different security levels. Thereby, both the exclusivity of the corresponding features and the possibilities for one
• the excitation of the phosphor according to the invention with UV radiation of different wavelength ranges may Example ⁇ example with the aid of suitable UV-LED, which can be operated in a stationary or pulsed, or using UV-emitting fluorescent lamp, preferably implemented using appropriate lamps of the CCFL type become.
• the detection of the luminescence radiation resulting in different excitation conditions can be carried out, for example, with the aid of suitable cameras, with the aid of photodiodes, which can optionally be combined with optical color filters, or with the aid of CCD lines or suitable spectrometers.
• the material is treated for several hours with 32% hydrochloric acid.
• the re-washed phosphor is post-doped with 0.1 g of Cu per kg of phosphor and after drying for 2 h at about 500 ° C getem ⁇ pert.
• the resulting example of the zinc sulfide phosphor according to the invention has the chemical formula which can be determined by a customary measuring method
• Fig. 3 shows emission onsspektren this example of Leuchtstof ⁇ fes invention, namely an emission spectrum 21 of electroluminescence, an emission spectrum 22 of the UV-A-excited photoluminescence and an emission spectrum 23 of the UV-B-excited photoluminescence.
• Example 1 There are 11.592 g ZnS, 33, 526 g CuS0 4 * 5H 2 0, 4, 032 g Bil 3 , 36.596 g AIF3 and 365.925g S as in Example 1 mixed intensively. Each 1/6 of the mixture is filled in each case with a quartz tray and with a graphite dish weighing 12 g
• Activated carbon per kilogram of phosphor contains, covered; the annealing cup is closed with a Quarzgutdeckel.
• the reaction takes place in a push through furnace under ⁇ 1 ⁇ 5 "6H 2 /95% N 2 atmosphere within 3 h at 850 ° C. to 1000 ° C.
• the material is treated for several hours with 32% hydrochloric acid.
• the re-washed phosphor is nachdotiert with 0.15 g Cu per kg of phosphor and annealed after drying for 2 h at about 500 ° C.
• Phosphor namely an emission spectrum 31 of the electroluminescence, an emission spectrum 32 of the UV-A excited photo- luminescence and an emission spectrum 33 of UV-B excited photoluminescence.
• Each 1/6 of the batch is filled in each case a quartz dishes and with a graphite shell, the 12 g of activated carbon each
• Kilograms of phosphor contains, covered; the annealing cup is closed with a Quarzgutdeckel.
• the reaction takes place under a 1.5% H 2 / 98.5% N 2 atmosphere at 850 ° C. to 1100 ° C. within 3 hours.
• the material is treated for several hours with 32% hydrochloric acid.
• the again washed phosphor is nachdotiert with 0.1 g of Cu per kg of phosphor and after
• the resulting example of the zinc sulfide phosphor according to the invention has the chemical formula which can be determined by a customary measuring method
• Phosphor namely an emission spectrum 41 of the electroluminescence, an emission spectrum 42 of the UV-A-excited photoluminescence and an emission spectrum 43 of the UV-B excited
• the material is treated for several hours with 32% hydrochloric acid.
• the rewashed phosphor is post-doped with 0.1 g of Cu per kg of phosphor and, after drying, annealed at about 500 ° C. for 2 h.
• the resulting example of the zinc sulfide phosphor according to the invention has the chemical formula which can be determined by a customary measuring method
• Phosphor namely an emission spectrum 51 of the electroluminescence, an emission spectrum 52 of the UV-A-excited photoluminescence and an emission spectrum 53 of the UV-B-excited photoluminescence.
• Fig. 7 shows TERMS ⁇ onsspektren this example of Leuchtstof ⁇ fes invention, namely an emission spectrum 61 of the electroluminescence, an emission spectrum 62 of the UV-A-excited photoluminescence and an emission spectrum 63 of the UV-B-excited photoluminescence.
• Example 1 104.55 g S as in Example 1 mixed intensively.
• the mixture is filled into quartz dishes and covered with a graphite dish; the Glühschale is picked ⁇ closed with a Quarzgutdeckel.
• a push-through furnace takes place under a
• the material is treated for several hours with 32% hydrochloric acid.
• the re-washed phosphor is post-doped with 0.1 g of Cu per kg of phosphor and after drying for 2 h at about 500 ° C getem ⁇ pert.
• the resulting example of the zinc sulfidic invention Phosphor has the chemical formula which can be determined by a customary measuring method
• ZnS Cuo, 001151A.U0, 000151AI 0, oo298Gao, ooo458lo, 0013 F0, oo895Bro, 00177 on. 8 shows emission spectra of this example of the phosphor according to the invention, namely an emission spectrum 71 of the electroluminescence, an emission spectrum 72 of the UV-A-excited photoluminescence and an emission spectrum 73 of the UV-B-excited photoluminescence.

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• 2013
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